JPH0238106B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to compounds useful in the preparation of aqueous dispersions of water-insoluble compounds. More specifically, the present invention relates to urethane dispersants used in the production of aqueous dispersions of resinous or high molecular weight compounds containing epoxy groups. In recent years, in the paint and plastics industry,
Much emphasis has been placed on converting organic solvents to aqueous systems. Reasons for this conversion include the increasing price of these organic solvents as well as the pollution problems caused by the escape of organic-containing compounds such as carbon-hydrogen into the atmosphere. It has long been known that epoxy group-containing materials have highly desirable properties when used in coatings and plastic formulations. Epoxy resins provide unique strength and chemical resistance to paints and plastic formulations. For these reasons, the use of epoxy resins, and in particular the use of aqueous emulsions or dispersions of epoxy group-containing materials, has increased recently. However, since epoxy group-containing materials have extremely high reactivity and relatively high molecular weights, it may be difficult to produce stable, low-viscosity epoxy resin dispersions with relatively high solids content. many. Therefore, there remains a need for dispersants that enable the production of epoxy resin dispersions with small particle size, low viscosity, and high solids content. One conventional method for producing such dispersions is to use an epoxy surfactant obtained by reacting 2 moles of hydroxy-terminated polyethylene glycol with 1 mole of diepoxide. However, it is difficult to fully react these materials without causing excessive chain elongation. Another problem that hinders the production of epoxy resin dispersions is the difficulty in producing satisfactory dispersants that are compatible with epoxy resins. The above and other problems are small granularity;
This problem is overcome by providing compounds of the present invention that can be used to prepare stable epoxy resin dispersions with low viscosity and high solids content. The compounds of the present invention are particularly useful in that they can be produced without excessive chain elongation. British Patent No. 1,069,735 discloses a process for the preparation of surface-active reaction products consisting of reacting 2 moles of diisocyanate, 1 mole of dihydroxypolyether and 2 moles of monophenol. However, this patent does not disclose the use of such reaction products as epoxy resin dispersants. US Patent No. 3,549,543 discloses a combination of materials useful as low foam agents, detergents and cleaning agents. This includes certain ethylene oxide adduct dimers made with aliphatic or aromatic diisocyanates. However, this patent does not disclose the specific compounds of the present invention, nor does it disclose the use of such materials as dispersants for polyepoxides. US Pat. No. 4,079,028 discloses the production of certain polyurethane-based materials using polyhydroxy compounds such as di- and trihydroxybenzenes. The hydroxy-terminated prepolymers produced in this patent are generally end-capped with either monoisocyanates or monoisocyanate/diisocyanate mixtures. This patent does not disclose the use of bisphenol A type compounds or their use with aliphatic polyether glycol monoethers. The present invention relates to the production of surfactants or dispersants for use in epoxy resin materials that are not originally water-soluble or water-dispersible. The dispersants of the present invention are prepared by reacting approximately n moles of aromatic, aromatic origin or cycloaliphatic diol, n+1 moles of diisocyanate, and 2 moles of long chain aliphatic polyether glycol monoether. Ru. This dispersant is represented by the following general formula. In the above formula, n is 1 to 10, D is the residue of an aliphatic polyether glycol, G is the residue of an aromatic, aromatic origin or alicyclic diol, F is the residue of a diisocyanate, and E is C ₁ The diisocyanate compounds useful in the _present invention can be represented by the general formula OCN-NCO.
Here, F is a residue of an aliphatic, aromatic, aromatic origin or alicyclic compound having about 6 to about 20 carbon atoms per molecule. Virtually any type of diisocyanate-containing material can be used in the present invention, the only requirement being that the diisocyanate backbone is
This means that it does not contain any groups that would interfere with the reaction between this and the diol and long-chain aliphatic polyether glycol monoether described below. Isocyanate is a conventionally known substance,
Suitable for the present invention are those which may be referred to as aromatic, aromatic origin or cycloaliphatic diisocyanates. The term "aromatic origin"
It refers to aromatic isocyanates or their precursors that are partially or completely hydrogenated to form cycloalkyl or cycloalkene isocyanates. The same applies to the diol used in the present invention, but it is preferable that the isocyanate is structurally similar to the polyepoxide that will ultimately be dispersed with the obtained dispersant. Therefore,
When a long-chain aliphatic epoxy resin is used, it is preferred to use long-chain aliphatic isocyanates such as hexamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, and the like. However, since in most cases the polyepoxides used have an aromatic backbone, such as bisphenol A, it is preferred to use aromatic, aromatic origin or cycloaliphatic diisocyanates. Particularly preferred diisocyanates include isophorone diisocyanate, bis(p-phenyl isocyanate), bis(p-phenyl)
Methylene diisocyanate, bis(p-phenylcyclohexyl) methylene diisocyanate,
2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,4-phenylene diisocyanate, 1,3-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate , 1,5-naphthalene diisocyanate, 1,4-cyclohexane diisocyanate, and the like. The second main component of the present invention is an aromatic, aromatic origin or cycloaliphatic diol. However, the term "aromatic origin" used here refers to partially or completely hydrogenated aromatic diols. Examples of diols useful in the present invention include resorcinol, hydroquinone, p,p'-dihydroxybenzophenone, p,p'-dihydroxybiphenyl, p,p'-dihydroxydiphenylethane,
Bis(2-hydroxynaphthylmethane), 1,5
-dihydroxynaphthalene, and p,p'-dihydroxydiphenylpropane (commonly known as bisphenol A). Furthermore, hydrogenated bisphenol A, 1,4-cyclohexanediol, 1,3-
Also included are cyclopentanediol, cyclohexanedimethanol, and the like. Other useful compounds are
Various halogenated derivatives of the above substances, such as polyhalogenated bisphenols including tetrabromobisphenol A. The third component of the present invention has the general formula E-O-D-O
It is a long chain aliphatic polyether glycol monoether represented by -H. However, in the above formula, E is
The _C1 - _C4 alkyl group and D each mean the residue of an aliphatic polyether glycol having a molecular weight of about 1000-15000. Preferred materials for use in the present invention are _C1 - _C2 monoalkyl ethers of polyoxyethylene glycol. Polyether products include polyethylene oxide addition products, which are polyethylene glycol polyethers, as well as about 50
Block copolymers of ethylene oxide and propylene oxide containing ~90% by weight ethylene oxide and about 10-50% by weight propylene oxide are included. The polyether glycol monoether used in the present invention is manufactured using methods well known in the art. The use of terms such as diisocyanates, diols or glycols in the above description is not meant to exclude materials consisting of mixtures of monofunctional and polyfunctional materials. In the case of such mixtures, the materials used need only contain on average approximately two functional groups. For purposes of this invention, the terms diisocyanates, glycols and diols encompass materials having on average about 1.5 to 2.8 functional groups per molecule. To prepare the compositions of the present invention, approximately 2 moles of the long chain monoalcohol (i.e., glycol monoether) are combined with n moles of diol and n+1
Moles of diisocyanate are reacted. Preferably, n is about 10 or less; higher molecular weights reduce effectiveness as an epoxy resin dispersant. Particularly preferred is n from 1 to about 5. Although there are many ways to co-react the three materials mentioned above, a particularly preferred reaction method is to first add the diol and long chain monoalcohol to the reactor. This mixture is then heated to melt (usually within the range of about 60-80°C). A reaction catalyst may be added at this point. Examples of reaction catalysts include virtually any type of catalyst that catalyzes the reaction between isocyanates, alcohols, and diols.
Such catalysts include tertiary amines and various organometallic compounds and carboxylates of metals such as tin, lead, mercury, and the like. Specific examples of such catalysts include trialkylamines and dialkyltin dialkoxylates, including dibutyltin dilaurate and the like. The amount of catalyst added to the reaction mixture can vary over a wide range depending on the desired reaction rate and the type of reactants used. However, in general, based on the total amount of reactants, approximately
0.1-5% by weight of reaction catalyst is added to the reaction mixture. Following the addition of the catalyst, the diisocyanate is added and the mixture is maintained at reaction temperature until all isocyanate groups have disappeared. The isocyanate reaction is monitored using standard laboratory techniques of taking a sample of the reaction mixture, adding an amine such as dibutylamine, and back titrating with an acid such as HCl. Usually about 1/2 to 2 hours of heating to reaction temperature is required for all isocyanate groups to react. The product thus obtained is then
It can be used as a dispersant or surfactant for various epoxy resins. Although the present invention can be used to disperse virtually any type of epoxy resin in water, the dispersant of the present invention is particularly useful for aromatic polyepoxide resins (this type of epoxy resin is due to its good hydrolytic stability). Such polyepoxides are well known in the art and are prepared by reacting diphenols of the type described above with at least an equivalent, preferably excess, of epihalohydrin, preferably epichlorohydrin, relative to the phenolic hydrogen. Preferred epoxy resins are from about 180 to
It is a glycidyl polyether of bisphenol A with an epoxy equivalent weight of 1000. Dispersion of epoxy resins with dispersants thus prepared can be accomplished by any of several methods well known in the art. A preferred dispersion method is to introduce the epoxy resin together with the dispersant into a reactor. The two materials are then heated in unison to melt the polyepoxide, if necessary, to obtain a compatible mixture. At this point it may be desirable to add up to about 30% by weight of cosolvent based on the total amount of polyepoxide and dispersant. Examples of such cosolvents include glycols, glycol ethers, and glycol esters, including ethyl cellosolve (monoethyl ether of ethylene glycol), butyl cellosolve (monobutyl ether of ethylene glycol), and cellosolve acetate (monobutyl ether of ethylene glycol). Also included are substances such as various cellosolves, such as monoethyl ether acetate (acetate ester of monoethyl ether) (Cellosolve is a registered trademark of Union Carbide Corporation). A co-solvent and a predetermined amount of water are added to the resulting mixture. The amount of water present and the temperature of the phase inversion point are important factors in producing emulsions of small and uniform particle size. At 80-95°C, the amount of water required is typically that required to form an emulsion of 72-77% solids. This mixture is then kept under stirring at the desired temperature until a stable dispersion is obtained. In some cases, it may be necessary to slightly increase the temperature to form a stable dispersion. Dispersion stability can be evaluated by monitoring its viscosity and maintaining the temperature until a stable viscosity is obtained. To achieve dispersion of the epoxy resin, at least about 2% dispersant should be used. The maximum amount of dispersant should be the minimum amount necessary to form a stable dispersion. Generally, about 15% or less based on the total weight of dispersed solids is sufficient. The amount of water in which the epoxy resin is dispersed also varies widely depending on the epoxy resin and dispersant used. However, the typical solids content of the final product is within the range of about 35-70% by weight. Another method of achieving dispersion of the epoxy resin is to mix the surfactant and water and then slowly add the epoxy resin to the mixture over a period of minutes to hours. If the epoxy resin used is a solid, it is necessary to heat this material to its melting point. The products produced according to the invention may be modified with conventional fillers, pigments, reinforcing agents as well as other conventional aqueous or aqueous-based binders, modifying agents, extenders, and the like. The obtained epoxy resin dispersion can be blended into a one-component or two-component system. In two-part systems, an epoxy curing agent such as an amine or amide/amine is added to the dispersion immediately before use. On the other hand, in a one-component system, the epoxy resin and curing agent are mixed from the beginning. In any of these systems, baking at temperatures of 100-200° C. for up to 1/2 hour is required to achieve final hardening. The dispersed products obtained according to the present invention are preferred as protective coatings, but can be used in a variety of plastic end uses, including. The most common application of this type of paint is in the field of industrial maintenance paints using two-component systems. The dispersion of the present invention can also be used as a coating for printed circuit boards. In the examples set forth below, all parts and percentages are by weight unless otherwise specified. Example 1 In a reactor equipped with a mechanical stirrer and a thermometer, 629.3
1 part MPEG-5000 and 28.7 parts bisphenol A were added. (MPEG-5000 is a methoxy-terminated polyethylene glycol polyether manufactured by Union Carbide with a freezing point of 59.2°C and a molecular weight of approximately 5000.) The reactor was gassed with nitrogen, and the mixture 60 to
Stir and heat to 80° C. at which point 0.7 parts of dibutyltin dilaurate was added. The temperature was then brought to 82°C and 42 parts of isophorone diisocyanate (equivalent
111) was added and the resulting reaction mixture was maintained at a temperature ranging up to about 100° C. for 2.5 hours. The resulting dispersant exhibited a Gardner-Holdt viscosity of O to P at 25° C. at 10% solids in water. Example 2 In a reactor equipped with a mechanical stirrer and a thermometer, 1164.0
1 part Epi-Rez 520 and 36.0 parts of the plain dispersant prepared in Example 1 were added. (Epi-Rez520 is a bisphenol A glycidyl polyether with a weight per epoxy of approximately 502
Commercially available from Specialty Resins Company. ) The two materials were heated continuously for approximately 20 minutes at temperatures ranging up to 115°C. Next, 168.0 parts of ethyl cellosolve and 232.0 parts of water were added to the reactor at a reactor temperature of about 95°C. (Ethyl cellosolve is the monoethyl ether of ethylene glycol and is commercially available from Union Carbide.) The mixture was then held at about 85° C. for 1 hour and 10 minutes, after which an additional 582.0 parts of water was added. the resulting mixture
The temperature was maintained at a temperature ranging from 85°C to 65°C for 1 hour and 15 minutes.
The epoxy resin dispersion thus obtained was 840 cps.
Burtskfield viscosity (no. 2 spindle and
(using a rotation speed of 20 rpm), and the particle size is 1.0~
It was within the range of 1.5μ. Example 3 Using essentially the same procedure as in Example 1, the dispersants shown in the following table were prepared. In Table 1, the "Type" column indicates the polyether used in the reaction, and the "Mole" column indicates the number of moles of the polyether. The "Poly(NCO)" column indicates the type and mole number of diisocyanate used. The “Bisphenol” column is
The number of moles of bisphenol A used in the reaction is shown. The "Reaction Temperature" column indicates the temperature used to prepare the polymer in °C; the "Viscosity" column indicates the temperature at 25 °C at 40% solids in water, unless otherwise stated.
The Gardner-Holdt viscosity of is shown. In Table 1, the following components were used. MPEG-5M is MPEG-5000, manufactured by Union Carbide, molecular weight approximately 5000, freezing point
Methoxy-terminated polyethylene glycol at 59.2°C. MPEG-2M is MPEG-2000, except that it has a molecular weight of approximately 1900 and a freezing point of 51.9°C.
It is a substance similar to MPEG-5M. MRS-10 is a polymethylene polyphenyl isocyanate with an isocyanate functionality of 2.4 and an isocyanate equivalent weight of 132, Mobay Chemical
Commercially available from Company. Des.W is Desmodur W., which is dicyclohexylmethane 4,4'-diisocyanate, also available from Mobay Chemical Company. IPDI is isophorone diisocyanate. TDI is toluene diisocyanate.

[Table] Example 4 According to the procedure described in Example 2, using the dispersants obtained in experiments E to K in Table 1,
An aqueous dispersion of Epi-Rez520 epoxy resin was prepared. The results are shown in Table 2. In this table, "dispersant (%)" refers to the weight percent of the dispersant used, and "solid content (%)" refers to the weight percent of the solid content in water of the dispersion.
“Viscosity” was measured at 25℃ using spindle number 2.
The Bruckfield viscosity at 20 rpm is given in cps, and "viscosity" is given as the percentage of the dispersed material within each of the three viscosity ranges given in μ.

[Table] Example 5 22.6 parts (0.024 epoxy equivalent) of the 55% solids dispersion in water described in Experiment E in Table 2 was mixed with 15.2 parts (0.028 effective amine hydrogen equivalent) of a polyamide amine curing agent having an amine hydrogen equivalent of 324. ) mixed with
This curing agent, Epi-Cure CT-60-8536, commercially available from Celanese Specialty Resins Company, salts 16% of the available amine nitrogen of the preferred amidoamine acetic acid polymer and converts the resulting salt into a 60/20 mixture of butyl cellosolve/ethyl cellosolve/toluene. /20
(Weight ratio) Diluted with a mixed solvent to a solid content of 60%. The resulting blend of epoxy resin and curing agent had a solids content of 43.7%. Thickness of this formulation 3
A coating of mill (0.08 mm) was prepared on a bonderized steel plate. This film is 2 to 3
After leaving it for a while, it became dry to the touch. After standing for 6 days at room temperature, the coating exhibited a pencil hardness of B to HB, with good surface abrasion resistance and excellent gloss and adhesion. The principles, preferred embodiments, and implementation methods of the present invention have been shown above. However, the specific embodiments disclosed above are illustrative and not intended to be limiting, and therefore the present invention is not limited to these embodiments. Various modifications may be made by those skilled in the art within the scope of the invention.

Claims (1)

[Scope of Claims] 1 Reaction product of n+1 mol of diisocyanate, n mol of aromatic, aromatic origin or cycloaliphatic diol and 2 mol of long-chain aliphatic polyether glycol monoether, where n is 1 to Ten)
A dispersant for aqueous epoxy resins. 2. The dispersant according to claim 1, wherein n is 1 to 5. 3. The dispersant according to claim 1, wherein the diisocyanate is an aromatic diisocyanate, the diol is diphenol, and the polyether glycol monoether is a _C1 to _C4 monoalcohol ether of polyethylene glycol. 4 General formula: (In the formula, n is 1 to 10, D is the residue of aliphatic polyether glycol polyglycol ether, and E is
_C1 - _C4 alkyl group, F means the residue of a diisocyanate, and G means the residue of an aromatic, aromatic origin or alicyclic diol, respectively) according to claim 1. System dispersant. 5. Claim 4, wherein D is a polyethylene glycol polyether residue, E is a _C1 - _C2 alkyl group, F is an aromatic diisocyanate residue, and G is p,p'-dihydroxydiphenylpropane.
Dispersant as described in section. 6 (a) forming a reaction product of n+1 moles of diisocyanate, n moles of aromatic, aromatic origin or cycloaliphatic diol, and 2 moles of long chain aliphatic polyether glycol monoether; (b) obtained A method for producing an epoxy resin dispersion, comprising: forming an aqueous dispersion of an epoxy resin using a reaction product produced by the reaction. 7 The reaction product is used in an amount of 2 to 15% by weight, based on the combined weight of epoxy resin and reaction product, and the solids content of the aqueous dispersion formed is 20 to 35% by weight. The method described in scope item 6. 8 The isocyanate is an aromatic diisocyanate,
The diol is derived from diphenol, the polyether glycol is derived from ethylene glycol, and the epoxy resin has a weight per epoxy group.
7. The method according to claim 6, wherein the bisphenol A diglycidyl ether has a molecular weight of 180 to 1000. 9. Process according to claim 6, in which up to 30% by weight of co-solvent is used, based on the total content of epoxy resin and reaction product.